JPS5588083A - Dry type developing device - Google Patents

Abstract

PURPOSE: To prevent the production of stains and obtain the images which are distinct up to the ends by providing defining members to a doctor blade and so forming the same that developing action gradually weakens from the boundary part of the effective image region toward the outer side.

CONSTITUTION: A doctor blade 35 is constituted by a laterally long blade plate 36 and defining plates 37a, 37b which are secured to the right and left both end parts of the top of said plate. The defining plates are formed by being curved along the outside peripheral surface of a rotary sleeve 33 by way of a gap narrower than the blade gap. Since there is also a magnetic field by the stationary magnet 34 even on the outer side of the defined position, part of developer 38 goes beyond the defining part and spreads to the outer side, thus having the gradually weakened developing action. Hence, there is no production of stains despite the strong electric fields at the boundary part of the effective image region and the images distinct up to the end parts may be obtained.

COPYRIGHT: (C)1980,JPO&Japio